Electrically driven fingernail trimmer

ABSTRACT

The housing of the trimmer provides a boss on top with upper surface round or preferably oval in contour, the boss extending arcuately downwardly and inwardly so that the fingertip may extend protectively under its top surface as the fingernail bears against an emery connected to a shaft rotated by a fractional horsepower motor within the trimmer housing. The emery wheel and motor shaft are connected in manner that they are assembled with the trimmer housing against displacement of the shaft in direction of its axis; the preferred contour of the top surface of the boss being preferably elliptical to give the best fingertip protection, as when a long fingernail is to be trimmed.

United States Patent 187, Portia, Ark. 211 AppLNo. 737,746 221 FiledJnnel7, 1968 [45] Patented Aug. 3, 1971 [54] ELECTRICALLY DRIVENFINGERNAIL TRIMMER 12 Claim, 5 Drawing Figs.

[52] US. l32/73.6 [51] Int. A4511 2905 [50] Fieldolseareh l32/73.6,

[56] ReferenoesClted UNITED STATES PATENTS 1,706,483 3/1929 Corbett172/179 2,389,665 11/1945 l-larris..... l32/75.8 2,597,525 5/1952Kessler l32/75.8

weeee FOREIGN PATENTS 1,355,632 11/1964 France 132/73.6 959,756 3/1957Germany l32/73.6

OTHER REFERENCES Science News Letter. Aug. 22, 1964, Vol 86 #8 page 124Primary Examiner- Louis G. Mancene Attomeywilliam E. Ford ABSTRACT: Thehousing of the trimmer provides a boss on top with upper surface roundor preferably oval in contour, the boss extending arcuately downwardlyand inwardly so that the fingertip may extend protectively under its topsurface as the fingernail bears against an emery connected to a shaftrotated by a fractional horsepower motor within the trimmer housing. Theemery wheel and motor shaft are connected in manner that they areassembled with the trimmer housing against displacement of the shaft indirection of its axis; the preferred contour of the top surface 'of theboss being preferably elliptical to give the best fingertip protection,as when a long fingernail is to be trimmed.

PATENTEU AUG 3 I97! w m m w R m 5 m R A TTOR/VE Y ELECTRICALLY DRIVENFINGERNAIL TRIMMER The invention relates to an electrically drivenfingernail trimmer of the type which provides an emery wheel upon a bossatop the motor housing in manner that the fingertip flesh may beprotected as it bears guidably against the downwardly and inwardlyextending side surface of the boss that is provided below the boss topsurface level.

The invention has the primary object of providing a fingernail trimmerof this class which mounts an emery wheel on a boss atop the housing inmanner to provide great and substantial protection under the top surfaceof the boss for the fingertip as the fingernail or the tip contacts theemery wheel.

As another important object the invention provides a fingernail trimmerof this class which includes means to connect the emery wheel to theupper end of the motor shaft in manner to inhibit axial displacement ofthe motor shaft with relation to the trimmer housing.

It is also another and further object of the invention to provide afingernail trimmer of this class which may be fractionally horsepowerdriven by a motor driven by a source of alternating current electricalpower, or by a direct current motor driven by storage battery meanswithin the motor housmg.

As yet an additional object, the invention provides a fingern'ailtrimmer of this class which has an emery wheel mounting boss atop themotor housing with upper boss surface being oval, preferably ellipticalin contour.

Other and further objects will be apparent when the specification hereinis considered in connection with the drawings, in which:

FIG. 1 is an isometric view of the top, front and one side of anelectrically driven fingernail trimmer comprising a preferred embodimentof the invention;

FIG. 2 is a plan view ofthe trimmer shown in FIG. 1;

FIG. 3 is a longitudinal sectional elevational view, taken along line3-3 of FIG. 2;

FIG. 4 is a transverse sectional elevational view taken along line 4-4ofFIG. 2; and

FIG. 5 is an elevational view of an emery wheel comprising amodification of the form of emery wheel shown in sectional detail inFIG. 4.

Referring now in detail to the drawings in which like reference numeralsare applied to like elements in the various views, a fingernail trimmeris shown in FIG. 1 as comprising a housing 11 with top 12, front 13 andleft side 14a; a switch 15 being shown centrally in the front 13;ventilation holes 16 being shown in the left side 140; an extension orconductor cord 17 being shown extending from the rear end of the trimmerl0; and a boss 18 mounting an emery wheel 19 being shown disposed abovethe housing top 12. Also, the right side 1412 is shown in front portionin FIG. I, and may be considered as having ventilation holes thereincorresponding with the holes 16 shown in the left side 14a.

As shown in FIGS. 2, 3 and 4, the top surface 20 of the boss 18 is shownas being in the form of an ellipse 21 in contour, with the emery wheel19 being shown as being of diameter to rotate within a counterbore, orrecess 22, with slight clearance thereinbetween. Also, in FIG. 2 theextension or conductor cord 17 is shown extending from a plug 23 whichis insertable into a receptacle 24, FIG. 3, so that the cord conductorwires 25a, 25b connect electrically with the respective conductor wires26a, 26b from the receptacle 24, within the housing 11 15 which closesthe contactors 31a, 31b is indicated as angular in shape with pivot 32near the apex of the angle, the switch being preferably of thetoggle-action type, which will stay closed, or stay open, untiloppositely pressed inwardly.

The motor 27 (or 28) includes a base flange or plate 33 which isconnected to the bottom or closure 34 for the housing 11 by means ofcountersunk head screws 35 passed inwardly through the aforesaid bottom34 and threaded through the flange or plate 33, as indicated in FIG. 3.As shown in FIG. 3, the bottom or closure 34 is pressfitted into thehousing 11. Ohviously other methods and structures for assembly may beconsidered. For instance, assembly may be completed by engaging thescrews 35 into threaded bores of projections extending inwardly from theunderside of the housing top 1 1.

As shown in FIGS. 3 and 4, the head of a screw 36 is embedded in afrustoconical hub 37 formed on the under side of the emery wheel 19.Correspondingly, concentric within the counterbore or recess 22 the boss18 is countersunk at 38 with the central bore 39 thereof receivingtherethrough the upper shank 40 of the screw 36. The boss 18 is shownbored with a larger diameter hole 41 from the underside, coaxial withthe central bore 39, so that the base of the hole or bore 41 provides adownwardly facing shoulder in restraint of further upward extension ofthe upper end of the motor drive shaft 42.

In order to assemble emery wheel 19 to be rotated with the motor shaft42, the upper end of the motor shaft 42 is inter- I nally threaded toreceive the reduced-diameter, externally to the fractional horsepowermotor 27 therein. As an altemative arrangement, the motor may be adirect current motor 28 with conductors 29a, 29b, to opposite sides ofdry cells 30a,

30b, series connected, all as indicated in dotted lines in FIG. 3.

With either arrangement, the conductor 260 (or 290 for a DC motor) willinclude switch contactors 31a, 31b therein, and thence the conductor 26awill connect into the motor, (say the positive side thereof). On theother hand the conductor 26b, (or 29b for a DC motor 28) will connectinto the opposite (preferably negative) side of the motor 27. The switchthreaded lower shank portion 43' of the emery wheel embedded screw 36.Thus the emery wheel 19 and motor shaft 42 are assembled with theaforesaid downwardly facing shoulder in the boss 18 restraining themotor shaft 42 against displacement in direction of its axis.

The boss 18 is shown as providing a downwardly extending pad 44 on theinner side thereof which is counterbored around the shaft bore 41 toprovide a recess to receive therein an antifriction means, as a bailbearing race 45a for the shaft 42. Also, a spacer or holddown ring 46ais shown about the shaft 42 to hold the upper ball bearing race 45a inplace. In like manner, an upwardly or inwardly projecting pad 46 isshown bored and counterbored in the housing closure 34 to provide a seatfor a ball bearing race 45b for the shaft 42. A holddown ring 46b isprovided about the motor shaft 42 to hold the lower ball bearing race45b in position against displacement.

Noticeably a setscrew 47 is shown passed transversely through thearcuately inwardly and downwardly extending side surface 48 of the boss18, below the boss top 20, just short of engaging the shaft 42 when thetrimmer 10 is in use. Then, when it is desired to disassemble the emery.wheel 19 from the drive shaft 42, the screw 47 is set up on to bind theshaft 42 against rotation, and the emery wheel 19 is turned in directionto disengage the lower threaded shank 43 of the screw 36 from the upperend of the aforesaid shaft 42. As an optional means for facilitatingdisengagement of emery wheel 19 from motor shaft 42, a screwdriver slot49 may be provided in the lower end of the shaft 42, and held while theemery wheel 19 is turned in direction to disengage the shank 43 for thedrive shaft end.

The front side 13 of the housing 11 extends substantially straightdownwardly with relation to the housing top 12, and so does the rearside 50, except for the recessed part which provides the receptacle 24.However, the left and right sides 14a and 14b have the surface beneaththe top formed concavely respectively along 51a, 51b, with the concavesurfaces running around the respective corners of the housing 11 to jointhe front and rear sides 13, 50. Thus there is provided such concavesurfaces 51a, 51b better to serve as finger grips when the trimmer 10 isin service.

Although the boss 18 may be of a round configuration, it neverthelessmust upstand as well as the shape of boss shown in FIGS. 3 and 4 mustupstand; and also there must be enough material outwardly of the recess22 to insure that the small rim of material around the emery 'wheel doesnot break out. See FIG. 4. However, preferably, the top 20 of the boss18 should be oval, as elliptical, for instance, and thus the fingertip52 to be protected, as best shown in FIG. 3 is spaced from thefingernail 53 to be trimmed, and in ample degree. The trimmer may alsobe employed to trim the sides of a fingernail 53, in which case theaforesaid side surface 48 of the boss 18 is arcuate or concave in ampledegree to protect the side flesh of a finger.

As shown in FIG. 5, a buffer 55 is installed on top of an emery wheel19, the emery wheel being otherwise as constructed in FIGS. l4,inclusive. The buffer 55 may be of the durable type that is ofsubstantially the life of the emery wheel, in which case its connectionto the emery wheel is substantial in nature.

Otherwise, where the buffer 55 is of comparably short life with regardto the emery wheel, then it will be expedient for the connection ofemery wheel and bufier to be easily disengageable, although positivelyeffective when an individual buffer is in service. In either case, sincethe means and method of connecting a fingernail buffer to a holdingmeans is conventional, it is not felt necessary to show connection indetail. For instance, in FIG. 5, the heavy line separating emery wheeland buffer may indicate that the buffer is glued or cemented to theemery wheel.

The invention is not limited to the particular structural arrangements,with alternatives shown, but other embodiments, forms, variations andimprovements are all considered, as long as such may fall within thebroad spirit of the invention, and within the broad scope ofinterpretation claimed for and merited by the appended claims.

What i claim is:

1. An electrically driven fingernail trimmer having a housing with alower side closure plate mounting a fractional horsepower motor, themotor shaft upper end portion extending centrally upwardly thereabove,said housing including a boss upstanding with axis normal to the topthereof, the top outer surface extending substantially parallel to saidclosure plate, the boss on top being at least one of round and ovalcontour with top surface being substantially parallel to said housingouter top surface and having a first bore centrally therethrough, saidboss being slightly recessed on top by slight counterboring and beingcountersunk downwardly below said slight recess to provide a centralrecess downwardly into said boss, an underside counterbore boredupwardly into said boss and of greater diameter than said first borethereabove thus to provide a shoulder with said motor shaft upper endportion to be received upwardly into said counterbore, connection meansextending through said bore to connect the motor shaft upper end portionand an emery wheel against axial displacement of said shaft with shaftend face to bear notatably against said shoulder, said boss on top beingat a predetermined spaced distance from said top and substantiallyparallel thereto, said boss extending sidewardly arcuately downwardlyand inwardly. to said housing top to provide such space relation as topermit a finger-to be placed fiat on the housing top leaving thefingernail exposed on the boss top whereby guidably to receive fingertipflesh to bear protectedly against said boss side surface and downwardlyguidably on said housing top surface as the nail of the finger isbrought to bear against said motor-rotated emery wheel.

2. An electrically driven fingernail trimmer as claimed in claim 1, inwhich said motor is connected by an extension cord to a source ofelectrical power.

3. An electrically driven fingernail trimmer as claimed in claim 1 inwhich said housing carries storage battery means therein connected tosupply the electrical power to drive said motor.

4. An electrically driven fingernail trimmer as claimed in claim 1 inwhich said boss top contour is round and is slightly recessed bycounterboring concentrically within said round contour with said emerywheel being disposed to extend above said recess and of slightly lesserdiameter than said counterbore.

5. An electrically driven fingernail trimmer as claimed in claim 1 inwhich said boss top contour is oval and is slightly recessed bycounterboring centrally within said oval contour with said emery wheelbeing disposed to extend above said recess and of slightly lesserdiameter than said counterbore.

6. An electrically driven fingernail trimmer as claimed in claim 1 inwhich said contour is oval in the form of an ellipse.

7. An electrically driven fingernail trimmer as claimed in claim 1 inwhich said contour is oval in the form of a 45 ellipse.

8. An electrically driven fingernail trimmer as claimed in claim 1 inwhich said motor is electrically connected to a plugreceptacle meansincluded by said housing.

9. An electrically driven fingernail trimmer as claimed in claim 1 whichincludes an extension cord with conductors from the motor extending fromsaid housing and being anchored with relation thereto and terminatingoutwardly in an insertable plug.

10. An electrically driven fingernail trimmer as claimed in claim 1 inwhich said emery wheel includes a buffer thereon.

11. An electrically driven fingernail trimmer as claimed in claim 1, inwhich said motor shaft has a screwdriver slot in the under end thereofwhereby said shaft may be held stationary as said emery wheel isdisengaged therefrom.

12. An electrically driven fingernail trimmer as claimed in claim I, inwhich said boss has a setscrew transversely thereinto to bear againstsaid motor shaft to hold said shaft stationary as said emery wheel isdisengaged therefrom.

1. An electrically driven fingernail trimmer having a housing with alower side closure plate mounting a fractional horsepower motor, themotor shaft upper end portion extending centrally upwardly thereabove,said housing including a boss upstanding with axis normal to the topthereof, the top outer surface extending substantially parallel to saidclosure plate, the boss on top being at least one of round and ovalcontour with top surface being substantially parallel to said housingouter top surface and having a first Bore centrally therethrough, saidboss being slightly recessed on top by slight counterboring and beingcountersunk downwardly below said slight recess to provide a centralrecess downwardly into said boss, an underside counterbore boredupwardly into said boss and of greater diameter than said first borethereabove thus to provide a shoulder with said motor shaft upper endportion to be received upwardly into said counterbore, connection meansextending through said bore to connect the motor shaft upper end portionand an emery wheel against axial displacement of said shaft with shaftend face to bear notatably against said shoulder, said boss on top beingat a predetermined spaced distance from said top and substantiallyparallel thereto, said boss extending sidewardly arcuately downwardlyand inwardly to said housing top to provide such space relation as topermit a finger to be placed flat on the housing top leaving thefingernail exposed on the boss top whereby guidably to receive fingertipflesh to bear protectedly against said boss side surface and downwardlyguidably on said housing top surface as the nail of the finger isbrought to bear against said motor-rotated emery wheel.
 2. Anelectrically driven fingernail trimmer as claimed in claim 1, in whichsaid motor is connected by an extension cord to a source of electricalpower.
 3. An electrically driven fingernail trimmer as claimed in claim1 in which said housing carries storage battery means therein connectedto supply the electrical power to drive said motor.
 4. An electricallydriven fingernail trimmer as claimed in claim 1 in which said boss topcontour is round and is slightly recessed by counterboringconcentrically within said round contour with said emery wheel beingdisposed to extend above said recess and of slightly lesser diameterthan said counterbore.
 5. An electrically driven fingernail trimmer asclaimed in claim 1 in which said boss top contour is oval and isslightly recessed by counterboring centrally within said oval contourwith said emery wheel being disposed to extend above said recess and ofslightly lesser diameter than said counterbore.
 6. An electricallydriven fingernail trimmer as claimed in claim 1 in which said contour isoval in the form of an ellipse.
 7. An electrically driven fingernailtrimmer as claimed in claim 1 in which said contour is oval in the formof a 45* ellipse.
 8. An electrically driven fingernail trimmer asclaimed in claim 1 in which said motor is electrically connected to aplug-receptacle means included by said housing.
 9. An electricallydriven fingernail trimmer as claimed in claim 1 which includes anextension cord with conductors from the motor extending from saidhousing and being anchored with relation thereto and terminatingoutwardly in an insertable plug.
 10. An electrically driven fingernailtrimmer as claimed in claim 1 in which said emery wheel includes abuffer thereon.
 11. An electrically driven fingernail trimmer as claimedin claim 1, in which said motor shaft has a screwdriver slot in theunder end thereof whereby said shaft may be held stationary as saidemery wheel is disengaged therefrom.
 12. An electrically drivenfingernail trimmer as claimed in claim 1, in which said boss has asetscrew transversely thereinto to bear against said motor shaft to holdsaid shaft stationary as said emery wheel is disengaged therefrom.